Brew in a bag partial boil

Question

Brew in a bag partial boil

TomSelleck

2016年2月29日 17:11

I was flipping through BrewDog's recently released catalog of their recipes and there are a couple I'd like to have a go at.

I was originally going to ask how to convert some of the recipes to extract but then did some reading about the brew-in-a-bag method.

So some quick questions with an example in mind:

In this recipe, the grain bill calls for Extra Pale - Maris Otter, Caramalt and Munich.

1) For the BIAB method - Do I simply add all the grain to a bag, insert into my kettle and hold at 65c / 69c for an hour?

2) Is it possible to use less water in the boil rather than the full volume? e.g Have ~17.5L boil and top up with cold water at the end?

Topic partial-boil biab brewing homebrew

Category Mac

Mołot · Accepted Answer · 2016年2月29日 17:11

Yes, you do simply put all grain (crushed!) in a bag. That's the point.

However Brewdog's catalog calls for fly sparging, something you simply won't do. With fly sparging, your extraction efficiency can be about 80%. Yesterday I hit 95% (again, against my plan, and I really hate it, but that's just btw). Even 90% should be perfectly doable. Without sparge, best reported results I have seen was at 70%. Usually worse. This means you need 20-25 percent more grain than a standard recipe. If you will just use bag without adjusting grain bill, your beer would turn out weak, watery, and tasteless compared to original. For first try, keep some DME at hand, to correct your wort if needed. Once you know your efficiency, you can calculate exact amount of grain to hit OG you need.

Using less water for boil is possible, but don't do it if you can avoid it. Full volume boil will allow you to extract hops just the way they did it. And that's the way if you want to brew a perfect clone. Less water can cause worse extraction of alpha acids. Also, it can promote maillard reactions - something you might want sometimes, but definitely does not look like planned in this recipe. Oh, and if you have to do a partial boil, top it with well boiled water, not just cold tap one.

Brew in a bag partial boil

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